0112, 0114, 0116
The basic landscape of this area is comprised of orange/yellow blocks and grey concrete floor tiles with a few scattered pipes sticking out of the ground.
From the Museum's entrance, you can use the elevator on the left to get to the ground floor and explore the area.
Along the top wall of the area is a doorway that will take you up a large tower structure made of the same orange blocks with many elevators leading to different parts of the tower. This area originally housed many things that can now be found in Flying Fish World, which replaced it in later versions. The elevators still work, but many of the places and rooms they lead to are now empty or nonfunctional. The only thing to note is a strange laughing tree at the far right of the roof accessible from the elevators. It was primarily the host world for the Spacesuit effect, Smile-san (also explaining the background music), the way to Space and many other features the Flying Fish World has by now.
Slightly east-southeast of the museum entrance is another doorway, leading to a large looping area known as Concrete World B (灰色の荒野, Haiiro no Arano, Gray Wildnerness), in which diamonds appear. If you press the action button, there will be one flashing diamond that rapidly changes colors, moving slowly in random directions as you chase it down. It will send you back to the main area, once interacted with.
- Concrete World was originally the main place where you could find Smile-San and the Spacesuit effect in previous versions of the game. Now this (and all its other previous features) have been moved to Flying Fish World. You can still travel up the elevators, but doorways that lead to particular places no longer work.
- It's important to note that BGM 055 can only be fully unlocked if you enter the elevator portions of Concrete World A.
- The map containing the elevator portion of Concrete World A is one of two largest single maps in the entire game, tied with the Underground Laboratory.
- Concrete World B had, in the older versions of Yume 2kki, a direct, one-way entrance directly from the Nexus.
- In older versions, it had a brighter color scheme.